How will kids with add act in class?

Multiple ways: It depends on the age and the type of adhd that they have. Some of the possible ways are: daydreaming, not staying on task, not focusing, not paying attention, easily distracted, making noises, disturbing others, out of their seat, talking too much, not waiting turn, interrupting others, being loud, missing assignments, having trouble with authority, not completing schoolwork, disorganized, etc.